Fix Cider dependency when not being present in the system

[pablodip]

User Story

As a developer I want to not have Cider installed in my system if I don't use it and the project work correctly.

As a developer I want the project to be editor agnostic so that it doesn't have extra dependencies related with editors.

Description

We don't have Cider as a dependency in the project.clj, since re removed it little time ago.

But we still use some Cider namespace in commiteth.core in the REPL server.

So right now the system gives an error if Cider isn't available somehow in the system:

�[0m�[91mjava.io.FileNotFoundException: Could not locate cider/nrepl__init.class or cider/nrepl.clj on classpath., compiling:(core.clj:1:1)

The thing is: why do we depend on Cider for the REPL if it is a tool for Emacs? I think that the project should be editor agnostic.